The present invention relates to a suspension used in for example a hard disk drive (HDD) apparatus and for supporting a drive IC chip for a thin-film magnetic head element, to head gimbal assembly (HGA) with the suspension and to a manufacturing method of an HGA.
In such HDD apparatus, the thin-film magnetic head element for writing magnetic information into and/or reading magnetic information from a magnetic disk is in general formed on a magnetic head slider flying in operation above a rotating magnetic disk. The slider is fixed at a top end section of the suspension.
Recently, recording frequency in the magnetic disk rapidly increases to satisfy the requirement forever increasing data storage capacities and densities in today""s HDDs. In order to realize higher frequency recording, proposed is a chip-on-suspension structure of an HGA with a suspension for supporting both a slider and a drive IC chip of a driver circuit for the magnetic head element. According to this structure, since the length of lead lines from the driver circuit to the magnetic head element can be shortened, generation of unnecessary noises from the lead lines can be effectively suppressed resulting high frequency recording characteristics to improve. Also, it is possible to amplify a very faint output signal provided from a magnetoresistive effect (MR) read head element at a nearer position to the MR head element.
The drive IC chip used in such chip-on-suspension structure HGA is required to extremely downsize due to its mounting configuration. If the drive IC chip is so downsized, its surface area becomes greatly small causing extremely insufficient thermal radiation. Because a writing current flowing through the drive IC chip during recording operation is very large, this insufficient heat radiation of the drive IC chip will become a significant problem. In addition, since the drive IC chip is mounted on a suspension with a very small mounting space and also an electrical characteristics of the drive IC chip will be deteriorated due to noises caused by floating capacitance of its lead terminals at a higher frequency more than 500 MHz, it is necessary to fabricate the drive IC chip as a bare IC chip. Thus, the heat radiation performance of the drive IC chip will more decrease and a chip temperature will dependently increase.
Usually, a spring member of a suspension is formed by a leaf spring of a stainless steel. However, since the stainless steel has a lower thermal conductivity in comparison with that of other metal material and the stainless steel suspension is formed in a quite thin thickness, a sufficient thermal radiation effect cannot be expected when the suspension of the chip-on-suspension structure HGA is mainly made of the stainless steel.
As aforementioned, according to the conventional HGA with the chip-on-suspension structure has the following problems:
(1) Since the drive IC chip is extremely thin and small and therefore has a small surface area, it is difficult to effectively radiate a heat generated by itself;
(2) Since a stainless steel generally used for the spring member of the suspension has a relatively low thermal conductivity and an extremely thin thickness, no sufficient thermal radiation effect can be expected if the HGA is configured with a normal chip-on-suspension structure; and
(3) Since the drive IC chip is mounted on a surface of the suspension, which is faced to a magnetic recording medium, it is difficult to attach a thermal radiation mechanism directly to the drive IC chip itself.
If heat is generated in chip and it is not sufficiently radiated from the drive IC chip and thus the temperature of the drive IC chip highly increases, not only operations of the drive IC chip becomes unstable but also a thermal deformation of the drive IC chip may occur.
It is therefore an object of the present invention to provide a suspension, an HGA and a manufacturing method of an HGA, whereby more effective heat radiation of a drive IC chip can be expected.
Another object of the present invention is to provide a manufacturing method of an HGA, whereby more effective heat radiation of a drive IC chip can be expected without substantially adding a new process to a conventional manufacturing process.
According to the present invention, a suspension includes a resilient flexure made of a stainless steel for supporting a magnetic head slider with at least one thin-film magnetic head element, a load beam made of a stainless steel, supporting the flexure, for applying a predetermined load to the magnetic head slider, a lead conductor member on which a drive IC chip with a circuit for the at least one thin-film magnetic head element is to be mounted, and a high-thermal-conductivity member made of a material with a higher thermal conductivity than that of the stainless steel and inserted between the lead conductor member and the load beam in a region containing at least a section on which the drive IC chip is to be mounted.
Also, according to the present invention an HGA includes a magnetic head slider with at least one thin-film magnetic head element, a resilient flexure made of a stainless steel, supporting the magnetic head slider, a load beam made of a stainless steel, supporting the flexure, for applying a predetermined load to the magnetic head slider, a drive IC chip with a circuit for the at least one thin-film magnetic head element, a lead conductor member on which the drive IC chip is mounted, and a high-thermal-conductivity member made of a material with a higher thermal conductivity than that of the stainless steel and inserted between the lead conductor member and the load beam in a region containing at least a section on which the drive IC chip is mounted.
The high-thermal-conductivity member with a higher thermal conductivity than that of the stainless steel is inserted between the lead conductor member and the load beam in a region containing at least a section on which the drive IC chip is to be or is mounted. Thus, not only a thermal capacity of the suspension can be increased but also heat generated from the drive IC chip can be transferred through this high-thermal-conductivity member and widely dissipated resulting the drive IC chip to effectively cool. Therefore, the temperature of the drive IC chip itself can be decreased and also elevation of the local temperature of the suspension around the drive IC chip can be suppressed. As a result, a stable operation of the drive IC chip can be expected, a thermal deformation of the suspension can be prevented, and a serious heat effect to the thin-film magnetic head element can be prevented.
It is preferred that the lead conductor member is formed on the flexure directly, and that the high-thermal-conductivity member is inserted and fixed between the flexure and the load beam in the region containing at least a section on which the drive IC chip is to be or is mounted.
It is also preferred that the lead conductor member is formed by a FPC (flexible printed circuit) member, and that the high-thermal-conductivity member is inserted and fixed between the FPC member and the load beam in the region containing at least a section on which the drive IC chip is to be or is mounted.
It is further preferred that the lead conductor member has a section for mounting the drive IC chip, located at a middle of the suspension.
It is preferred that the suspension or the HGA further includes a base plate fixed to a base section of the load beam, and that the lead conductor member has a section near the base plate, for mounting the drive IC chip. In this case, preferably, the high-thermal-conductivity member is inserted and fixed between the base plate and the load beam in the region containing at least a section on which the drive IC chip is to be or is mounted.
It is also preferred that the high-thermal-conductivity member is a metal member made of a metal material containing one of Al, Cu, Mg, Al alloy, Cu alloy and Mg alloy.
According to the present invention, further, a method of manufacturing an HGA includes a step of inserting a high-thermal-conductivity member made of a material with a higher thermal conductivity than that of a stainless steel between a resilient flexure made of a stainless steel and a load beam made of a stainless steel, supporting the flexure, for applying a predetermined load to a magnetic head slider with at least one thin-film magnetic head element, a step of fixing the flexure and the load beam with each other, a step of mounting a drive IC chip with a circuit for the at least one thin-film magnetic head element on the flexure, and a step of mounting the magnetic head slider on the flexure.
Also, according to the present invention, a method of manufacturing an HGA includes a step of inserting a high-thermal-conductivity member made of a material with a higher thermal conductivity than that of a stainless steel between a load beam made of a stainless steel, for applying a predetermined load to a magnetic head slider with at least one thin-film magnetic head element and a base plate fixed to a base section of the load beam, a step of fixing the load beam and the base plate with each other, a step of fixing a resilient flexure made of a stainless steel to the load beam, a step of mounting a drive IC chip with a circuit for the at least one thin-film magnetic head element near the base plate, and a step of mounting the magnetic head slider on the flexure.
The high-thermal-conductivity member made of a material with a higher thermal conductivity than that of a stainless steel is inserted between the flexure and the load beam or the base plate and the load beam, and then the flexure and the load beam or the base plate and the load beam are fixed to each other. The HGA can be fabricated only by adding a simple process for inserting and fixing the high-thermal-conductivity member between the flexure and the load beam or the base plate and the load beam to the conventional manufacturing process. As a result, the manufacturing process will not be complicated and therefore an HGA capable of performing more effective heat radiation from a drive IC chip can be provided without increasing a manufacturing cost and a manufacturing time.
It is preferred that the fixing step includes spot-welding the flexure or the base plate and the load beam at a plurality of points.
It is also preferred that the high-thermal-conductivity member is a metal member made of a metal material containing one of Al, Cu, Mg, Al alloy, Cu alloy and Mg alloy.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.